ADS – APPLICATION IN FILTER DESIGN - Layout Nurul Husna Mohd Rais Soh Ping Jack

Presentation Outline Filter Design Process & Implementation Filter Design Example Implementation using Distributed Elements Lumped Element to Stubs Conversion Selecting & Placing Components Description of Components Board Parameters

Filter using Distributed Elements Filter Design Process & Implementation Remember this process? Low-pass Prototype Design Filter Specification Scaling & Conversion Done using ADS Optimization & Tuning Filter Implementation Etc etc…. Filter using Distributed Elements Filters using stubs

Filter Design Example Example Design a low pass filter for fabrication using microstrip lines. The specifications are: cutoff freq of 4 GHz, third order, impedance of 50 ohms and a 3dB equal ripple characteristics g1 = 3.3487 = L1 g2 = 0.7117 = C2 g3 = 3.3487 = L3 g4 = 1.0000 = RL

Implementation using Distributed Elements

Lumped Element to Stubs Conversion

Selecting and Placing Elements To select a specific element, ensure that the “Tlines Microstrip Components” tab is selected. Specific element are sorted into these categories as shown in the box below

Selecting and Placing Elements - MLIN To insert the MLIN component into the schematic, click on the specific element in the bottom box and drag till an outline of the element appear as shown. Click again to place the element

Selecting and Placing Elements - MLOC To insert the MLOC into the schematic, click on the specific element in the bottom box and drag till an outline of the element appear as shown. Click again to place the element

Description of Components MSUB component General substrate characteristic of printed circuit board MLIN component Represents short lengths of microstrip transmission line used in LPF. MLIN1 Correspond to transmission line section 1.

Board Parameters Set the characteristics of the substrate “MSUB1” as to H = 0.813mm, T = 0.035, Er =3.8, and Cond = 5.8E+07 (conductivity of copper). The rest of the parameters leave as default. The parameters dialog box for MSUB can be invoked by doubling clicking on the MSUB component. Set the characteristic W and L of each MLIN components. The filter specification, physical parameters, and the even and odd mode line must be enter into LineCalc.

Board Parameters To design a low pass filter on a RT/Duroid 6002 board with the following parameters: tanδ = 0.019 εr = 3.38 Metallization Layer Thickness (t) = 35 um Substrate Height (h) = 0.813 mm Desired Freq Range (f) = 4 GHz

Board Parameters Board Cross Section & Substrate Definition tanδ = 0.019 εr = 3.38 Metallization Layer Thickness (t) = 35 um Substrate Height (h) = 0.813 mm Conductivity = 5.8e+07

W and L from LineCalc Tool To obtain the value of physical dimension (W & L) of component, LineCalc from ADS tool. Click Tools>LineCalc>Start LineCalc

Presentation Outline Filter Design Process & Implementation Filter Design Example Implementation using Distributed Elements Lumped Element to Stubs Conversion Selecting & Placing Components Description of Components Board Parameters Dimensions from LineCalc Inserting

Dimensions from LineCalc Tool

Dimensions from LineCalc Tool Substrate Parameters εr = 3.38 Miur = 1mm H = 0.813mm Hu = 0.813mm T = 0.035 Cond=5.8E7 TanD = 0.019 Component parameters Freq = 4GHz Electrical Z0 = 50Ω E_eff = 90degres

Dimensions from LineCalc Tool Z0 L W 50 12.657700 1.334800 64.9 12.666600 0.870356 70.3 12.680300 0.748376 217.5 13.220500 0.006193

Inserting Dimensions Doble click the MLIN component and insert the L and W value obtain from the LineCalc.

Filter Implementation

Generating Layout

Generating Layout